Darwin on microscopes, 12; on Ascidians, 13. Devil’s Coach Horse, 57. Dipping-tubes, 23. Dissecting microscope, 18. Dissection, mode of, 37. Diving Spiders, 108. Dugès on Water Mites, 117. Dung Beetle, 119. _Dytiscus marginalis_, 31; etymology of, 33 _n._; breaking of shells by, 33; Sowerby on, 34; description of, 35; food of, 36; anatomy of, 37; habits of, 41; Kirby on, 41; Sir J. Lubbock on, 42; Professors Lowne and Miall on, 45; Dr. Sharp on, 47; abdomen of, 47; breathing of, 48; larva of, 157; Swammerdam on, 158, 159; Mr. Burgess on, 160. Earwig, 75. Edriophthalma, 129. Elytra, 41. _Epeira diadema_, description of, 98; web of, 98; J. A. Thomson on, 100; Dr. Butler on, 100; Blackwall on, 101, 102; mode of taking its prey, 102; Hudson on, 103; feet of, 104; spinnerets of, 105. Evans, W., on Sialis, 177. _Field_, the, quoted, 33, 35. Forceps, 22. _Forficula auricularia_, 75; Kirby and Spence on, 76; De Geer on, 76; young of, 76; forceps of, 77; anatomy of, 77; Butler on, 79; Dr. Sharp on, 79. Formalin, 24. Forty-legs, 122. Fresh-water Shrimp, 142. _Gamasus coleoptratorum_, 119. _Gammarus marinus_, 146; Dr. J. Salter on, 147. _Gammarus pulex_, 142; anatomy of, 144. Geer, De, on Forficula, 76; on Locusta, 80; on Water Mites, 116; on Beetle Mites, 120; on Lithobius, 123; on Julus, 126; on larva of Limnobia, 167; on Paraponyx, 172. Geophilus, 124. _Geophilus crassipes_, 125; Mr. Pocock on, 125. Glass block, 22. Glass box, 22. Glass slips, 22. Gosse on Prawns, 133. Graber on Corixa, 95. Grasshopper, Great Green, 80. Great Water Beetle, 49. Hart, Mr., on Paraponyx, 173. Harvestmen, 96. Hemiptera, 86. Hill, Dr., on Nepa, 90. Hudson on Spiders, 103. Hundred-legs, 122. Hunting Spiders, 98. Hydrachna, 113. _Hydrachna globula_, 118 _n._ Hydrophilus, larva of, 164; Lyonnet on, 164. _Hydrophilus piceus_, 49; Bateman on, 50; legs of, 53; Simmermacher on, 53; breathing of, 54; cocoons of, 54; Lyonnet on, 54. Hymenoptera, wings of, 170. Idotea, 143. _Idotea pelagica_, 155. Illinois State Laboratory, mode of collecting in, 25. ‘Insects,’ 27; divisions of, 32. Invertebrates, 28. Isopods, 152. Julus, 121, 124. _Julus terrestris_, 126; De Geer on, 126; Dr. Sharp on, 126. Jumping Spiders, 105. Kew, Mr., on dispersal of shells, 130. Kirby on Dytiscus, 41; on Ocypus, 59; on Forficula, 76; on Locusta, 83; on insect noises, 84; on Salticus, 107.